Grounding device



March 12, 1957 w G. HINES 2,785,344

GROUNDING DEVICE Filed March 9, 1953 131.1. 6 M

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United States Patent "cc GROUNDING DEVICE 7 William G. Hines, West Hartford, Conn. Application March 9, 1953, Serial No. 341,266

Claims. (Cl. 317-2) This invention relates to a grounding device and is embodied in an electrically conductive strip of material which is attachable to a shoe for grounding the human body to prevent an accumulation of electro-static charges therein.

Said device is intended for persons who are required to Work in an explosive atmosphere or in a place where an explosive atmosphere is liable to develop and is particularly useful, for example, in the operating rooms of hospitals since the use of anaesthesias is liable to result in the presence of an explosive atmosphere which could easily be ignited by the spark which usually occurs on the discharge of a substantial amount of static electricity from a persons body.

The body grounding devices heretofore produced have been in the form of special shoes, or attachments for shoes, which were cumbersome and uncomfortable to the wearer and which were also unsightly thereby causing objection from people such as nurses or hospital personnel Who were required to wear such devices.

An object of this invention is to provide a grounding device in the form of a conductive strip of material which is attachable to a persons shoe and which can be worn without discomfort.

A further object of this invention is to provide such a device which, when attached to a shoe, will be disposed in a position to warrant a good electrical contact with a persons body.

Another object of this invention is the provision of a grounding device which may be detachably secured to a shoe to permit removal thereof When the shoes are worn in other locations.

A still further object of this invention is to provide a removable grounding device having novel means for retaining it in position on the shoe and for preventing discomfort to the wearer as he walks.

Further objects and advantages of this invention will be more clearly understood from the following description and the accompanying drawings in which:

Fig. 1 is a side view of the rear portion of a shoe, partially in section, and illustrating my improved grounding device and the manner in which it is secured to said shoe.

Fig. 2 is an end view of the rear portion of said shoe further illustrating the grounding device.

Fig. 3 is a fragmentary view of the conductive strips forming the grounding device.

Fig. 4 is a view similar to Fig. 1, but illustrating a modified form of my invention.

Fig. 5 is a bottom view of the heel of a shoe illustrating the manner in which the modified grounding device is secured in position thereon.

Fig. 6 is an enlarged fragmentary view of one of the conductive strips utilized in said modified form.

Fig. 7 is a sectional view taken on line 6-6 of Fig. 5.

Referring to the drawing, the numeral 5 denotes the heel of a conventional shoe and 6 the rear portion of the Shoe upper. My improved grounding device is composed 2,785,344 Patented Mar. 12, 1957 of two strips 7 and 8 of an electrically conductive material; the strip 7 being preferably made of a wire cloth which has a high degree of conductivity and yet is light in weight and very thin, and the strip 8 being preferably made of an electrically conductive rubber of which many types are commercially available. Each of said strips 7 and 8 is provided with a coating of a suitable pressure sensitive adhesive 9 on one side thereof and said strips are joined together by a suitable electrically conductive separable fastener 10 as illustrated in Figs. 1 through 3, one element of said fastener being carried by each of said strips.

The device is applied to the shoe by securing the conductive rubber strip 8 to the underside of the heel and up the rear side thereof as illustrated in Figs. 1 and 2. The pressure sensitive adhesive 9 on said strip 8 will securely fasten it to said heel. The strip 7 is then secured to the rear of the shoe upper 6, over the edge 6a thereof, down into the interior of the shoe and over the heel portion of the insole 6-11 in a position wherein it will extend under the heel of the wearers foot. The adhesive 9 on the strip 7 will retain said strip on the shoe and will prevent it from becoming detached therefrom as the person walks.

The provision of the conductive strip 7 which is of a sufficient length to extend into the shoe and to a position under the wearers heel is of great importance as it assures a good electrical contact with the persons body although a stocking is being worn since the underside of a persons foot is usually damp from perspiration which moistens the heel of the stocking and renders it electrically conductive. In addition, the weight of the persons body will press the heel firmly against the conductive strip to thereby further assure a good contact.

It is apparent that any electrical charges in the persons body will pass through the conductive strips 7 and 8 to ground and that an accumulation of electro-static charges, is therefore, prevented.

Should the conductive rubber strip 8 become worn, it may be removed from the heel and detached from the strip 7 through the separable fastener 10. A new strip 8 may then be secured to the heel and attached to the strip 7 by interengagement of the fastening elements comprising said fastener 10.

The modified form of my invention illustrated in Figs. 4 through 7 includes a strip of conductive wire cloth 7-a, similar to the strip 7, and a strip of conductive rubber 8-a which is similar to the strip 8 above described. Said strips 7-a and S-a are joined by a separable fastener 10-a, but are not provided with the adhesive as in the preferred form of my invention illustrated in Figs. 1 through 3.

The strip 7a has a bendable metallic member 11 secured against its inner surface by means of a piece of pressure-sensitive adhesive tape 12 and an elastic band 13 is secured to the free end of the rubber strip 8-a as illustrated in Fig. 4.

The grounding device embodying the modified form of my invention is secured to a shoe by placing the rubber strip 8-zz against the underside of the heel 5 and up the back thereof. The elastic band 13 is then placed around the heel and over the portion of the strip 8-a extending up the back of the heel to thereby secure it in position. The wire cloth strip 7a is then placed against the rear portion of the shoe, as illustrated in Fig. 4, and the flexible metallic member 11 is bent over the edge of the shoe upper and thus imparts to the strips 7-a a sufficient stiffness to prevent it from Working out of the shoe or from becoming wrinkled as a person walks. it will be noted that in the modified form of my invention the strap 7-a is made of a sufi'icient length to extend en 3 tirely under a persons heel for the reasons above set forth.

It will be understood on inspection of the drawings that the thickness of the various materials included in the-two forms of my grounding device have, of necessity, been exaggerated to Clearly show the invention. Actually, said elements are very thin and, when applied to a shoe, cause no discomfort whatsoever to the wearer and second strip of conductive material adapted to extend into said shoe and over a portion of the insole thereof wherein it will be engaged by the Wearers heel, and electrically conductive separable fastening means detachably securing said strips together.

2. For a shoe, a grounding device comprising a first strip of conductive material having a coating of adhesive on o'ne side thereof for securing a portion of said strip to the underside of the shoe, a second strip of conductive material having a coating of adhesive thereon for securing said strip to the shoe upper and being of a suflicient length to extend from the end of said first strip into the interior of the shoe and over the insole thereof and a conductive separable fastener element secured to one end of each of said strips; said elements being engageable to electrically connect said strips.

3. For a shoe, a grounding device comprising a strip of pliable conductive material, means. for securing a portion of said strip against the underside of the shoe; said strip being of a suflicient length to extend therefrom over 4 the edge of the opening in the upper of said shoe and into the interior thereof to a position overlying the heel portion of the insole of said shoe, and a bendable member secured to said strip and adapted to be folded over the edge of said opening to retain said strip within the shoe.

4. For a shoe, a grounding device comprising a first strip of conductive material, a resilient member secured to the end of said strip and adapted to encircle the heel of said shoe for securing said strip thereto, a second strip of conductive pliable material adapted to extend from the end of said first strip over the edge of the opening in the upper of said shoe and into theinterior thereof to a position overlying the insole of said shoe, and means detachably securing said strips together.

5. For a shoe grounding device comprising a first strip of conductive material, a resilient band secured to one end of said strip for attaching said strip to the heel of the shoe, a second strip of conductive material adapted to extend from the free end of said first strip over'the edge of the opening in the shoe upper and into the interior thereof into foot engaging position, a bendable member carried by said second strip intermediate its ends and foldable over said edge to retain said strip in position, and a conductive fastener element carried by each of said strips, said elements being engageable to electrically connect said strips.

References Cited in the file of this patent UNITED STATES PATENTS 

